1. Field of the Invention
The present invention relates to a nuclear power plant construction preparation unit, a nuclear plant construction system, and a nuclear power plant construction method.
Priority is claimed on Japanese Patent Application No. 2011-004740, filed Jan. 13, 2011, the contents of which are incorporated herein by reference.
2. Description of Related Art
As a maintenance operation performed inside the nozzle at the inlet part and outlet part of a nuclear reactor vessel, there has been conventionally known a type of construction work (hereunder, referred to as INLAY work), in which the surface of the welded portion between a nozzle on the vessel side and piping is shaved off, and overlay welding is re-performed thereon with a material with a high level of corrosion resistance.
In this type of INLAY work, on the portion which undergoes the INLAY work, that is, on the portion to be welded, operations such as preliminary examination, groove processing, welding, weld flattening, and final inspection are carried out in this order.
Since the interior of the nozzle, which undergoes these operations, is exposed to an environment into which it is difficult for humans to enter, for devices (such as the preliminary examination device, shaving device, welding device, weld flattening device, and inspection device) corresponding to the respective operations above, there is provided a unique positioning reference for each device based on the dimensions of the nuclear reactor vessel in the drawings.
Incidentally, for example, Patent Document 1 discloses an operation performed inside the nozzle.
Patent Document 1 discloses an inner surface monitoring device and an automatic welding device such that: a monitoring sensor is arranged on the groove back surface side of the piping; and when the groove is welded by a welding device at the time of performing root pass welding, the fusion state associated with this welding is image-captured by the monitoring sensor, and the information associated with this image capturing is displayed on the monitor display.